This is to propose studies on: 1) Further isolation and characterization of blood group Ii-determinants of human erythrocyte membranes and from tumor tissue. 2) Preparation of antibodies directed to a well-defined i and I structures and the reactivity of antibodies directed against such antibodies. The candidate for this antigen will be prepared from H-active fucoganglioside as described above and from H3-glycolipid of human erythrocyte membranes. 3) Glycoside and Forssman status of human tumors and normal human tissues in caucasian populations and enzymo-genetical studies of Forssman synthesis from globoside.